Where do I purchase my plumbing?

I want to build my system. I don't have problem finding woods or PVCs. My problem is finding the valves that can fit into the holes that I am going to drill on the fish tank, on the grow beds, or on my buckets. I talked to Home Depot, Lowes, HD Supply employees. I couldn't get anything out. How do you build those connections?

Are you asking about the valves, or the seal in the tank where the pvc goes through?

If it is the seals, use UNISEAL, available on AMAZON. Just Google it.They work very well. Dont drill your holes until you get the seals. For better water flow, I suggest you get a size larger than you were originally thinking. I first used 1 1/2 inch but then went up to 2".

I too use Uniseals (also available online at pentairaes.com) in certain applications, but I use bulkhead fittings (aka tank fittings) in other situations. Up to 1" diameter, for supply (not drain) lines, you can get such fittings at local hydroponics stores. I think they have another name for them. Above 1", you can sometimes find them at irrigation supply stores (Horizon on Broadway in downtown Sac, Irrigation Supply Co in Woodland, etc.) but not consistently and not in a wide range of sizes. I typically get them from pentairaes.com. I bet they are also available on this site (theaquaponicsource.com).

I prefer bulkhead fittings to Uniseals for autosiphons because you can pull the standpipe entirely out of the fitting to drain the growbbed if you like, or to change standpipe length.